The Virtual Observatory will place all data into digital archives that can be searched by astronomers, students or the general public. To prevent data loss, a replica of each archive will be stored at a mirror site.

Centralising public access to scientific information in this way is not a new concept. GenBank, for example, provides information about genomics via the internet.

But astronomy is unlike other forms of science because the body of information is vast and constantly changing.

One night's observation, for example, requires a few hundred gigabytes of memory, and then the data needs to be calibrated for the transmission of the atmosphere and for the response of the instruments.

This constant correction is not an exact science. "With each new understanding of how corrections should be made, the data are reprocessed and recalibrated," write Szalay and Gray.

Astronomy data remains active for much longer, therefore, than data in other disciplines. One of the difficulties facing the designers is that the system must use current technology, but will still need to work in 50 year's time.

The team is anticipating great changes in computing over this period. "Advances in computational statistics will be essential to the success of the Virtual Observatory," comment the authors.

The project also aims to reduce the gap between cutting-edge research and public education.

"The Virtual Observatory offers the opportunity to teach science in a participatory way," say Szalay and Gray.

"We can give students direct access to a wonderful scientific instrument. They can use it to make discoveries on their own."